Experimental Studies: (1) Incorporation of amino acids into proteins will be studied in synaptosomal and myelinated axon fractions by biochemical and ultrastructural radioautographic methods. (2) Myelin proteins from rabbit optic nerve will be isolated after intraocular or intracranial injection of labeled amino acids. By polyacrylamide gel electrophoresis the contribution to the myelin protein from the retinal ganglion cells (via axoplasmic flow) and from the glial cells will be assessed. (3) RNA will be investigated in axons and presynaptic endings by combined biochemical and radioautographic methods. This investigation will include four studies. It will be determined (a) whether the RNA present inside the axon is provided by axoplasmic transport or has a different origin; (b) whether or not RNA is present at the presynaptic ending; (c) whether RNA-precursors migrate by axoplasmic transport; and (d), whether axonal RNA changes during development, during axonal regeneration and in abnormal conditions of myelin. (4) The effect of malnutrition on synapses will be assessed using a combined morphological and chemical analysis of the synaptosomal and other subcellular fractions from cerebral cortex. Clinical Studies: (1) The mode and site(s) of glycogen accumulation will be studied morphologically and biochemically in fibroblasts from patients with Pompe's disease. (2) Combined morphological and biochemical studies will be performed in Lafora bodies isolated from an unfixed brain.